|Budget Amount *help
¥3,000,000 (Direct Cost: ¥3,000,000)
Fiscal Year 2003: ¥900,000 (Direct Cost: ¥900,000)
Fiscal Year 2002: ¥800,000 (Direct Cost: ¥800,000)
Fiscal Year 2001: ¥1,300,000 (Direct Cost: ¥1,300,000)
Experiments of syntheses of the superheavy elements have been made more or less empirically, because there have been no reliable reaction theory for such unstable systems. Nevertheless, we want to synthesize as heavier elements as possible in order to know how many elements exist. According to the experiences, production rates decrease dramatically as the charge number Z of the element increases and thus, machine time is required enormously. Therefore, it is crucial to know optimum conditions for the productions, in other words, precise theoretical predictions of excitation functions for xn reaction channels, which is exactly the purpose of the present project. Now, it is achieved, as is shown in the publications, the list of which is attached below.
Most unknown theoretically was mechanisms of the fusion of massive heavy ions which leads to the formation of superheavy compound nuclei. We have employed a Langevin Approach, which was firstly proposed by the head investigator of the prese
nt project for description of nuclear collective motions, and was found to be successful for fusion of heavy ions and subsequent fission. We have developed the unique theoretical framework, i.e., the two-step model for synthesis of superheavy elements, which is now recognized as a canonical theoretical model, and was presented in the 2nd International Conference on Chemistry and Physics of Transactinide Elements, held at Napa, California, USA, Nov. 16-20, 2003, as an Introductory Review of Nuclear Reaction Theory.
Furthermore, we have succeeded in reproducing the available data of the experiments with so-called hot and cold fusion paths. Now, we are making predictions on the elements Z=113 and 114, which are expected to be useful in planning experiments, and at the same time, are waiting for experimental confirmation. A new statistical code has been developed which enables us to follow time evolution of the cooling process of the superheavy compound nuclei. This is now open for potential users. Less